CONCLUSIONS

The Keck/ACTS remote observing project has allowed us to experiment with remote observing on the Keck Telescope with a bandwidth not yet available to Hawaii via terrestrial networks. We have compared a variety of paradigms and tools for remote operations, and evaluated the performance of local tools over a large-bandwidth, long-delay network connection. Our work has led to a number of conclusions, many of which are applicable to ground-based remote observing efforts and non-astronomical communications satellite experiments:

1.

Remote observing techniques have the potential to save appreciable expenditures in terms of money and time, while simultaneously enabling increased levels of collaboration in the observing process. In the case of an observatory with large numbers of observers, short observing runs, and/or a very remote site, these savings may very well outweigh initial network costs to enable remote observing.

2.

The portable design of the Keck Telescope and instrument control systems has enabled remote observing to be implemented with only relatively minor software modifications. However, additional tools are needed over those available on-site to create a collaborative environment among the remote observing astronomers and the on-site telescope staff. Such tools are becoming widely available with the expansion and increasing popularity of the Internet.

3.

At the current time, high-speed terrestrial networks are the most viable source for adequate bandwidth to enable true remote observing. While the ACTS system is not sufficiently robust to enable remote observing, this testbed project suggests that future commercial-grade communications satellites may provide the reliability and affordability necessary for high-bandwidth remote software applications.

4.

The most outstanding problem regarding the viability of geosynchronous communications satellites for Internet-based software applications concerns the performance of the standard TCP/IP protocol over high-bandwidth, long-delay time networks. Although the initial set of extensions (i.e., RFC 1323) provide some relief, and several groups (e.g., Mitre Corporation) are working on this problem, its solution may determine the ultimate role for satellite communications in the WAN market.

Acknowledgments:

The research described in this paper was performed primarily at the California Institute of Technology and at the Center for Space Microelectronics Technology at the Jet Propulsion Laboratory. It has been sponsored by the National Aeronautics and Space Administration, Office of Advanced Concepts and Technology, under grant BK-509-20-42-00-00. The W. M. Keck Observatory is operated as a scientific partnership between the California Institute of Technology and the University of California. It was made possible by the generous gift of the W. M. Keck Foundation, and the support of its late president, Howard Keck. We also wish to thank Jimi Patel and Carl McFadden, our ground station operators at JPL and Tripler Army Medical Center, respectively, and Jon Chock, the Keck Observatory Systems Administrator, for their crucial assistance for the entire duration of this project. The scheduling and operations staff for ACTS have been extremely accommodating as well.